To find the area of the triangle you need to multiply the base and the length, which is directly perpendicular to the base. After multiplying, you will divide the product by 2 to get your answer, this is because a triangle is half a rectangle.
For the perimeter, I assumed that the empty side was a 5, please correct me if I am wrong. But to find the perimeter you need to add all the sides together, so I got 22.
